Reprogramming of energy metabolism is one of the hallmarks of cancer, since tumour cells need to
fuel their high proliferation rates. Warburg et al. first observed that cancer cells largely limit their
method of energy production to glycolysis only. In order to compensate for lower ATP yields,
cancer cells often upregulate expression of glucose transporters, typically GLUT1, which
substantially increases extracellular glucose import into the cytoplasm.